Other contamination sources
Equipment
Contamination of equipment occurs dur-
ing production, as well as when the equip-
ment is idle. Even with hygienic design
features, equipment can collect microorgan-
isms and other debris from the air, as well as
from employees and materials. Product con-
tamination of equipment is reduced through
improved hygienic design and more effective
cleaning.
Employees
Of all the viable means of exposing
microorganisms to food, employees are
the largest contamination source. Employ-
ees who do not follow sanitary practices
contaminate food that they touch, with
spoilage and pathogenic microorganisms
that they come in contact with through
work and other parts of the environment.
The hands, hair, nose, and mouth harbor
microorganisms that can be transferred
to the food during processing, packaging,
preparation, and service by touching, brea-
thing, coughing, or sneezing. Because the
human body is warm, microorganisms pro-
liferate rapidly, especially in the absence of
hygienic practices.
After the chain of infection is broken the
spreading of bacteria from one location
to another can be prevented. Generally,
the mishandling of food by people perpetu-
ates the chain of infection until someone
becomes ill or dies before corrective actions
are taken to prevent additional outbreaks
(Chao, 2003). If every person that handles
food could achieve appropriate personal
hygiene, food contamination could be mini-
mized. Every employee involved with food
manufacturing can play a very important
role in preventing food contamination.
Air and Water
Water serves as a cleaning medium during
the cleaning operation and is an ingredient
added in the formulation of various
processed foods. It can also serve as a source
of contamination. If excessive contamina-
tion exists, another water source should be
obtained, or the existing source should be
treated with chemicals (such as ultraviolet
units) or other methods.
Contamination can result from airborne
microorganisms in food processing, packag-
ing, storage, and preparation areas. This
contamination can result from unclean air
surrounding the food plant or from contami-
nation through improper sanitary practices.
The most effective methods of reducing air
contamination are through sanitary prac-
tices, filtering of air entering the food pro-
cessing and preparation areas, and
protection from air by appropriate packag-
ing techniques and materials.Sewage
Raw, untreated sewage can contain
pathogens that have been eliminated from
the human body, as well as other materials of
the environment. Examples are microorgan-
isms causing typhoid and paratyphoid
fevers, dysentery, and infectious hepatitis.
Sewage may contaminate food and equip-
ment through faulty plumbing.
If raw sewage drains or flows into potable
water lines, wells, rivers, lakes, and ocean
bays, the water and living organisms such as
seafood are contaminated. To prevent this
contamination, privies and septic tanks
should be sufficiently separated from wells,
streams, and other bodies of water. Raw
sewage should not be applied to fields where
fruits and vegetables are grown. (Additional
discussion related to sewage treatment is pre-
sented in Chapter 12.)